A typical image-based check processing system includes a check processing transport which has a document track and a number of check processing modules positioned along the document track for performing specific document processing operations on document items including checks moving downstream along the document track. The check processing system also includes a transport processor which executes a transport application program which is stored in memory to control operation of devices contained within the check processing modules positioned along the document track and thereby to control operation of the check processing transport.
A typical check processing transport includes a hopper into which a stack of document items is placed. An operator initially prepares the document items (e.g., orienting document items properly (forwards and upside right), removing staples, removing paper clips, straightening bent corners, and the like) before they are placed into the hopper. A document feeder adjacent the hopper selectively feeds or drives each document item from the stack of document items in the hopper to transport the document item from the upstream end to the downstream end along the document track past a magnetic ink character recognition (MICR) reader and an image capture device. The MICR reader reads a codeline from each document item. The image capture device captures an image of the front of the document item and an image of the back of the document item. The document items are eventually transported to sorting pockets of a pocket device located at the downstream end of the document track. The pockets receive document items which have been sorted based upon the particular transport application program.
From time to time, a double feed condition occurs (e.g., two overlapping checks) when only one check should have been fed along the document track. The occurrence of a double feed condition causes an undesirable result. A double feed condition of checks would result in one of the checks being missed and not processed. Eventually at some later time during balancing, it takes up much time from a human operator to locate the unprocessed check and then to reprocess it to complete the balancing function. This is time-consuming and costly.
Different ways of detecting a double feed condition of checks in an image-based check processing system are known. One known way to detect a double feed condition of checks is to use double feed detect sensors. A drawback in using double feed detect sensors is the number of false detections (i.e., a sensor indicating that a double feed condition has occurred, but when in fact a double feed condition has not occurred). A false detection of a double feed condition takes up some time from a human operator, but not as much time as would be taken up to locate and process a missing check caused by a true detection of a double feed condition.
Another known way to detect a double feed condition of checks in a check processing system is to determine if a captured image of a check has a proper MICR codeline. As an example, if the length of a MICR codeline from a check image is determined to be longer than the longest possible MICR codeline, then this would indicate an overlap of two checks. As another example, if the number of codeline field groupings from a check image exceeds the maximum possible number of codeline field groupings, then this would indicate an overlap of two checks.
Still another known way to detect a double feed condition of checks in a check processing system is to determine if a captured image of a business type of check has a proper image length. If the length of the check image is determined to be longer than the longest possible check length for a business check, then this would indicate an overlap of two checks. It would be desirable to provide methods of detecting a double feed condition of checks in a check processing system so that double feed detection is improved without having to take up more human operator time.